"Pediatric Infectious Diseases" — Practice

Question 1

A 10-month-old had three days of fever to 40 degrees, and today the fever has gone and a maculopapular rash has appeared. Diagnosis?

Accepted Answer

B

Question 2

Which is given in every case of childhood diarrhoea?

Accepted Answer

C

Question 3

A neonate has microcephaly with periventricular calcification and failed newborn hearing screening. Which infection?

Accepted Answer

C

Question 4

A 9-month-old has cough and a respiratory rate of 54 with no chest indrawing and no danger signs. Classification and management?

Accepted Answer

A

Question 5

Which is a general danger sign requiring urgent referral in a child aged 2 months to 5 years?

Accepted Answer

B

Question 6

A 6-year-old with dengue has been febrile four days. The fever settled today. Pulse 130, capillary refill 3 seconds, blood pressure normal, haematocrit risen from 36 to 45, platelets 40,000. What is happening and what is required?

Accepted Answer

The child has entered the critical phase of dengue and is in compensated shock from plasma leakage.

The counterintuitive element is that defervescence marks the onset of leakage rather than recovery. Increased capillary permeability allows plasma to escape the intravascular space over roughly 24 to 48 hours beginning as the fever settles, and this is when shock develops.

The rising haematocrit with the falling platelet count is the objective warning sign, and the two moving together is what distinguishes haemoconcentration from bleeding. Here the haematocrit has risen by 25 percent from baseline, indicating substantial plasma loss.

The normal blood pressure is entirely misleading. Children maintain pressure by tachycardia and vasoconstriction until very late, so a pulse of 130 with a capillary refill of 3 seconds and a normal pressure describes compensated shock, not stability.

Intravenous crystalloid is required now, with frequent reassessment of haematocrit and perfusion. Platelet transfusion is not indicated on the count alone in the absence of significant bleeding.

Question 7

An 18-month-old has had fever and weight loss for six weeks and the father is on treatment for pulmonary tuberculosis. Sputum cannot be obtained. Explain the diagnostic approach and why it differs from an adult.

Accepted Answer

Every difference from adult practice follows from one fact: children have paucibacillary disease.

Because the bacillary load is low, sputum smear is usually negative even when disease is present, and a child of eighteen months cannot produce sputum at all. Gastric aspirate, collected in the early morning before the swallowed overnight secretions are cleared, or induced sputum, is used instead.

Because bacteriological confirmation frequently fails, the diagnosis is assembled rather than proved. The components are contact history, which here is strong and is often the single most useful item, symptoms of persistent unremitting fever with failure to gain weight and loss of playfulness, tuberculin testing, and chest radiography.

The urgency comes from age. Immature immunity means children progress from infection to disease more often and faster than adults, and under two years the risk of disseminated and meningeal disease is high. Tuberculous meningitis develops over weeks with a prodrome of irritability and behaviour change, and outcome depends almost entirely on the stage at which treatment begins.

For non-severe drug-susceptible disease, WHO now recommends four months of treatment rather than six in children aged 3 months to 16 years, following the SHINE trial. Household child contacts should also receive tuberculosis preventive therapy.

Question 8

Why does fever persisting after the measles rash has appeared indicate a complication, and what are the late neurological sequelae?

Accepted Answer

The natural course of uncomplicated measles is that fever peaks with the appearance of the rash and then subsides over the following two to three days as the rash begins to fade. Continuing fever therefore means something else is now driving it.

Measles causes profound transient immune suppression, depleting existing immunological memory as well as impairing current responses, which is why secondary bacterial infection is common. Pneumonia is the commonest and is the leading cause of death in measles; otitis media and diarrhoea follow.

Two neurological complications are examined. Acute post-measles encephalitis occurs within days of the rash and is thought to be immune mediated rather than a direct viral effect.

Subacute sclerosing panencephalitis occurs seven to ten years after the acute illness, and results from persistent defective measles virus in the central nervous system. It presents insidiously with declining school performance and personality change, then myoclonic jerks, then progressive neurological deterioration, and is uniformly fatal. Risk is highest in children who contracted measles under two years of age, which is one of the strongest arguments for timely first-dose vaccination.

Vitamin A is given in every case on two consecutive days, because measles depletes stores precisely when they are needed for epithelial repair and immune function.

Question 9

Why is the febrile child without a focus managed so differently at 3 weeks, 2 months and 2 years of age?

Accepted Answer

Because the probability of serious bacterial infection, and the reliability of clinical assessment, both change steeply with age.

At three weeks the immune system handles encapsulated and intracellular organisms poorly, the organisms differ from those in older children and include group B Streptococcus, Escherichia coli and Listeria, and clinical signs are almost entirely non-specific. A septic neonate may be hypothermic, quiet and feeding poorly rather than febrile and irritable. Because examination cannot exclude meningitis, full evaluation including lumbar puncture, admission and empirical antibiotics is standard.

At two months risk is intermediate. Investigation is still required, but validated low-risk criteria combining appearance, laboratory results and social circumstances may permit closer observation instead of full empirical treatment.

At two years, in a fully immunised child, the risk is low and clinical assessment becomes reliable, because a child of this age who is alert, playful and drinking is behaving in a way a septic child cannot imitate.

Two further points shape the approach. Urinary tract infection remains the commonest occult serious bacterial infection throughout, and gives no urinary symptoms in infancy, so urine testing is routine rather than symptom-driven. And conjugate pneumococcal and Haemophilus vaccination has made occult bacteraemia uncommon, which is precisely why immunisation status is stated in stems.

Practice — "Pediatric Infectious Diseases"

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